Wheel kit for snowmobiles

ABSTRACT

A wheel kit replaces the skis of a snowmobile with a spring mounted front axle having steerable wheels secured thereto by separate kingpins and having leaf springs disposed in an outward flare, and another wheel kit replaces the endless drive track of the snowmobile with a swing frame having its forward end pivotally supported at the axis of the transverse drive shaft of the snowmobile generally beneath the engine at the front end, and having its rear end supported on a transverse shaft carrying a pair of adjacent rear drive wheels with means driving the same from said transverse drive shaft and with resilient means supporting the rear end of the snowmobile upon the swing frame.

United States Patent [1 1 Kiekhaefer WHEEL KIT FOR SNOWMOBILES [76]Inventor: Elmer Carl Kiekhaefer, 2408 Cypress Gardens Rd., Winter Haven,Fla. 33880 [22] Filed: Oct. 21, 1971 [211 App]. No.: 191,396

Sessions German printed App. No. 1,961,977, 6

[ 1 Nov. 27, 1973 Primary ExaminerRichard J. Johnson AttorneyElwin A.Andrus [57 ABSTRACT A wheel kit replaces the skis of a snowmobile with aspring mounted front axle having steerable wheels secured thereto byseparate kingpins and having leaf springs disposed in an outward flare,and another wheel kit replaces the endless drive track of the snowmobilewith a swing frame having its forward end pivotally supported at theaxis of the transverse drive shaft of the snowmobile generally beneaththe engine at the front end, and having its rear end supported on atransverse shaft carrying a pair of adjacent rear drive wheels withmeans driving the same from said transverse drive shaft and withresilient means supporting the rear end of the snowmobile upon the swingframe.-

9 Claims, 9 Drawing Figures Pmgmmuuvmzs I 3.774.706

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35m N [F 1 INVENTOR. iELMER CARL KIEKHAEFER WHEEL KIT FOR SNOWMOBILESBACKGROUND OF THE INVENTION This invention relates to a wheel kit forsnowmobiles and which replaces the customary front skis with a pair ofsteerable wheels, and replaces the customary endless track whichnormally supports and drives the snowmobile with a pair of rear drivewheels adapted to be driven by the snowmobile engine.

The principal objective of the invention is to provide a readyconversion of a snowmobile into a wheeled vehicle which thereby extendsthe useful life of the snowmobile to all of the year round asdistinguished from normal use limited to a winter season.

Various attempts have been made heretofore to convert snowmobiles towheeled vehicles for this purpose with structures that present variousproblems as to installation, mobility, stability, controllability andsafety of the driver.

SUMMARY OF THE INVENTION According to the present invention the kitconsists of two sub-kit assemblies, one to replace the front skis on thesnowmobile, and the other to replace the endless track supporting anddriving the snowmobile.

The first sub-kit assembly comprises a frame adapted to be rigidlysecured beneath the body of the snowmobile and a front wheel and axleassembly resiliently carried by the frame and providing for steering ofthe wheels with connections to the steering mechanism for the frontskis.

According to one embodiment of the invention, the second sub-kitassembly comprises a swing frame adapted to pivot on the axis of thetransverse drive or sprocket shaft beneath the engine, with resilientmeans supporting the snowmobile body on the rear end of the frame anddrive wheels disposed to support the rear end of the frame upon theground. A suitable positive drive connection is carried by the framebetween the engine and the wheels.

' Where chains are employed for the drive connection, a countershaft iscarried by the frame intermediate the front drive shaft and the reardrive wheel shaft or axle, and means are provided for tightening thechain between the front drive shaft and the countershaft and fortightening the chain between the countershaft and the drive wheel axle.

According to another embodiment of the invention, the swing frame ispivoted upon the countershaft and the latter is carried by the fixedframe of the first kit.

In both embodiments the front kit frame is rigidly attached to thebearing supports for the sprocket shaft to correlate the torsion andfore and aft forces between the two kit assemblies.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings furnished herewithillustrate the best mode presently contemplated for carrying out theinvention as described hereinafter.

In the drawings:

FIG. 1 is a side elevation of a conventional snowmobile;

FIG. 2 is a side elevation similar to FIG. 1 showing the snowmobileafter conversion to a wheeled vehicle by the kits of the presentinvention;

FIG. 3 is a front elevation of the construction of FIG.

FIG. 4 is a detail view showing the shock absorber and spring mountingfor the front axle;

FIG. 5 is a bottom plan view of the construction of FIG. 2;

FIG. 6 is an enlarged detail view taken on line 66 of FIG. 5 and showingthe adjustment of the countershaft for tightening the front chain;

FIG. 7 isan enlarged detail view taken generallyon line 77 of FIG. 5 andshowing the shock absorbers and adjustment for the rear axle fortightening of the rear chain;

FIG. 8 is an enlarged sectional view taken on line 88 of FIG. 7; and

FIG. 9 is a bottom plan view schematically showing a second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 of the drawingillustrates a conventional snowmobile having a rigid body 1 with anengine 2 at the front end and providing a seat 3 to the rear of theengme.

The front end of body 1 is normally supported upon a pair of laterallyspaced skis 4 which are connected to be steered by the handle bars 5.

The rear end of body I is normally resiliently supported by an endlesstrack assembly 6 having an endless belt 7 driven by suitable cog wheels8 on a transverse drive shaft 9 beneath the engine 2.

Drive shaft 9 is mounted in suitable end bearings in the frame of body Iand chain It) drives a sprocket 11 thereon from a sprocket 12 on theengine 2.

In converting the snowmobile of FIG. I to a wheeled vehicle the frontskis 4 and the endless track assembly 6 are removed and replaced by thefront and rear kits of the present invention as illustrated in FIGS. 2to 9, inclusive. 7

The front kit comprises a rigid frame 13 having side rails 14 adapted tobe bolted to the side brackets 15 beneath body 1 and which served tosecure the resilient mounting for the endless track assembly 6 of FIG.1.

The side rails 14 are rigidly spaced by a cross bar 16 at their forwardends, a rear cross bar 17, and intermediate cross bars 18 and 19. Thecross bars 16 to 19 are preferably welded to the side rails 14.

A rigid front axle 20 extends transversely of the body 1 just forwardlyof cross bar 16, and has kingpins 21 at its outer ends for mounting theassemblies for corresponding front steerabble wheels 22.

The steering of wheels 22 is accomplished by a steering arm 23 formed asa part of the steering knuckle at the corresponding kingpin 21, andwhich arm is connected by a link 24 to an arm 25 on the lower end of thesteering mechanism controlled by steering bar 5.

The front axle 20 is resiliently connected to rigid frame 13 by a pairof leaf springs 26 having their rear ends pivotally secured to cross bar19 by corresponding brackets 27 near the middle of the cross bar, andtheir forward ends diverging outwardly from each other and secured tothe axle 20 near the corresponding kingpins 21. Each spring 26 extendsfreely through a bracket 28 the necessary vertical resilient support forthe front end of the vehicle, and as means to prevent the front axlefrom rolling under brake torque thereon.

A pair of hydraulic shock absorbers 29 are preferably mounted betweenaxle 20 and the corresponding ends of the front cross bar 16, and serveto limit the vertical movement of axle 20 relative to the snowmobilebody.

The construction of the front kit just described provides a very stablesupport for the front end of body 1 with the steerable wheels 22 spacedwidely apart and readily connected to the steering mechanism of thesnowmobile. The triangular arrangement of the springs 26 with each otherand the axle 20 provides a very stable mounting for the body 1 whichtends to resist lateral sway and prevent shimmy.

The rear kit comprises a swing frame 30 comprising two spaced side rails31 having their forward ends spaced and pivotally mounted by suitablebearings upon drive shaft 9. The side rails 31 converge toward the rearand merge into a parallel rear portion 32 having vertical side plates 33welded thereto for mounting the rear axle shaft 34 in adjustablebearings 35.

A sprocket 36 is secured on shaft 9 near the center of the shaft andwhich drives a chain 37 extending to a sprocket 38 on a countershaft 39mounted in bearings 40 in side rails 31 intermediate the ends of thelatter. Countershaft 39 drives rear axle 34 by means of a sprocket 41 onshaft 39, chain 42 and a sprocket 43 on axle 34.

Suitable rear drive wheels 44 are secured to the opposite ends of axle34 for supporting and driving the converted snowmobile. For this purposethe wheels 44 are disposed rearwardly of body 1 and are generally withinthe overallwidth of the body so that the danger of injury to a driver orpassenger from possible contact with the drive wheels in case of anaccident is greatly reduced.

The front chain 37 may be tightened by adjustably moving bearings 40rearwardly relative to side rails 31 by the adjusting screws 45 threadedthrough a cross plate 46 secured between rails 31, and which screws bearagainst flanged mounting plates 47 carrying the corresponding bearings40. The mounting plates 47 have longitudinal slots 48 therein forreceiving bolts 49 which secure the plates in adjusted position to thecorresponding side rails 31.

The rear chain 42 may be tightened by moving the bearings 35 rearwardlyrelative to the side rails 31. For this purpose each bearing 35 has aslotted side plate 50 secured to the outer side of the correspondingside rail 31 and plate 33 by bolts 51 passing through the slots.Suitable adjusting bolts 52 extend forwardly through rear flanges 53 atthe rear ends of side rails 31, and through flanges 54 on side plates 50to adjust the latter longitudinally on the side rails.

The rear end of body 1 is resiliently supported on swing frame 30 by twolaterally spaced combination coil spring and hydraulic shock absorberassemblies 55 disposed between a cross member 56 on swing frame 30 and apivotal bracket 57 on a part 58 secured to the rear end of side rails14.

The part 58 comprises an upstanding rectangular frame on each side rail14 at the rear end thereof, and which frame is adapted to fit upwardlyin the channel space beneath the body 1 as shown in FIG. 8.

Relativelateral movement between the side rails 31 and the rear end ofbody 1 is prevented by means of inwardly facing vertical wear plates 59against which the ends of cross member 56 bear and slide.

Wear plates 59 are supported against displacement by the vertical posts60 of part 58.

The rear posts 60 have inward flanges 61 at the lower ends thereof whichserve as stops to be engaged by cross member 56 and prevent the swingframe 30 from dropping further away from the snowmobile body, whentraveling forward over rough ground.

Suitable hydraulic brakes 62 may be provided for the wheels 22 and therear drive shaft 34.

Fenders 63 may be provided over the wheels 22 and 44 to protect thedriver and improve the appearance of the unit.

In operation the converted snowmobile is driven over the ground by rearwheels 44, and the swing frame 30 provides a means for positivelydrivingly connecting the wheels to the drive shaft 9 and engine 2, andfor resiliently supporting body 1.

In the modified construction of FIG. 9, the swing frame 64 is shorterthan swing frame 30 and is pivoted at its forward end upon the forwarddrive shaft 65 which corresponds to countershaft 39 and is mounted insuitable bearing in side rails 14 of frame 13.

The forward drive shaft 65 is driven from shaft 9 by a chain 66 and inturn the shaft 65 drives the rear wheel drive shaft 34 by chain 67.

This construction enables locating cross bars 18 and 19 farther to therear and lengthening of the leaf springs 26.

The shorter swing frame reduces the unsprung weight and provides forgreater vertical movement of wheels 44 relative to body 1.

In both embodiments the drive shaft 9 may be the original sprocket shaftof the snowmobile, but it may be more convenient to provide a substituteshaft with the necessary drive sprockets thereon and which fits into thesame mounting as the snowmobile sprocket shaft.

The shaft 9 constitutes the connection between the front and rear kitsfor the purpose of transmitting tortional forces or twist therebetween.

For this purpose each end bearing 68 for shaft 9 in in body 1 of thesnowmobile has a plate 69 bolted thereto and which extends adjacent tothe corresponding side frame 14 of the front kit and is welded theretoto tie the front kit rigidly to the shaft mounting.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

We claim:

1. A wheel conversion device for snowmobiles having a chassis supportedat least in part upon an endless track mechanism with a front driveshaft, adapted to replace the track mechanism therefor and comprising arigid swing frame pivoted at its forward end on a horizontal transverseaxis to the snowmobile chassis, a pair of laterally spaced rear wheelsdisposed on opposite sides of the rear end of said swing frame andextending rearwardly beyond the end of the chassis, a rear drive shaftcarrying said wheels and mounted at the rear end of said frame, means todrive said rear drive shaft from a forward drive shaft disposed at saidpivotal connection between the chassis and said swing frame, andresilient means adapted to support the rear end of the chassis upon saidswing frame.

2. The construction of claim 1 in which the drive connection betweensaid forward drive shaft and said rear drive shaft comprises anintermediate countershaft carried by said swing frame at the pivotaltransverse axis therefor, a positive drive connection between said frontdrive shaft and said countershaft, and a positive drive connectionbetween said countershaft and said rear drive shaft.

3. The construction of claim 2 and separate means to adjust saidcountershaft and said rear drive shaft longitudinally of said frame.

-4. The construction of claim 1 and means adapted to be disposed at therear end of said snowmobile chassis for limiting relative lateralmovement of the chassis and frame.

5. The construction of claim 1 in which said rear drive wheels areadapted to be disposed directly behind the snowmobile chassis.

6. The construction of claim 1 wherein a separate wheel kit is adaptedto replace the steerable front skis of the snowmobile and comprises arigid front axle with a kingpin at each end supporting correspondingsteerable wheels spaced outwardly of the position for the snowmobilechassis, means adapted to connect said steerable wheels with thesteering mechanism for the snowmobile skis, and means adapted toresiliently support the front end of said snowmobile chassis upon saidfront axle.

7. A front wheel kit adapted for replacement of the front skis of asnowmobile, comprising a rigid transversely extending frame adapted tobe secured to the underside of the snowmobile when the front skis andtheir mountings have been removed, a front wheel axle having kingpinsfor separately mounting front steerable wheels at its opposite ends,means adapted to connect the steering knuckles of said wheels to thesteering control mechanism of the snowmobile, and resilient meansmounting said axle to said frame and providing for limited relativevertical movement between said axle and said frame.

8. The front wheel kit of claim 7 in which said last named meanscomprises a pair of leaf springs secured at their forward ends to theopposite ends of said axle and secured at their rear ends to said rigidframe near the longitudinal center line thereof.

9. A wheel mounting for snowmobiles having forward skis and a trackdrive with a forward sprocket drive shaft, comprising in combination afront wheel kit adapted to replace the forward skis of the snowmobileand a rear wheel kit adapted to replace the track drive for thesnowmobile, means mounting said rear wheel kit for vertical pivotalswinging on the sprocket drive shaft near the forward end of thesnowmobile with the wheels disposed beyond the rear end of thesnowmobile and driven from said shaft, and means rigidly mounting saidfront wheel kit to the bearing supports for said sprocket drive shaft,whereby torsional forces between the front and rear wheels are resistedto provide greater stability for the snowmobile when the wheel kits aresecured thereto.

1. A wheel conversion device for snowmobiles having a chassis supportedat least in part upon an endless track mechanism with a front driveshaft, adapted to replace the track mechanism therefor and comprising arigid swing frame pivoted at its forward end on a horizontal transverseaxis to the snowmobile chassis, a pair of laterally spaced rear wheelsdisposed on opposite sides of the rear end of said swing frame andextending rearwardly beyond the end of the chassis, a rear drive shaftcarrying said wheels and mounted at the rear end of said frame, means todrive said rear drive shaft from a forward drive shaft disposed at saidpivotal connection between the chassis and said swing frame, andresilient means adapted to support the rear end of the chassis upon saidswing frame.
 2. The construction of claim 1 in which the driveconnection between said forward drive shaft and said rear drive shaftcomprises an intermediate countershaft carried by said swing frame atthe pivotal transverse axis therefor, a positive drive connectionbetween said front drive shaft and said countershaft, and a positivedrive connection between said countershaft and said rear drive shaft. 3.The construction of claim 2 and separate means to adjust saidcountershaft and said rear drive shaft longitudinally of said frame. 4.The construction of claim 1 and means adapted to be disposed at the rearend of said snowmobile chassis for limiting relative lateral movement ofthe chassis and frame.
 5. The construction of claim 1 in which said reardrive wheels are adapted to be disposed directly behind the snowmobilechassis.
 6. The construction of claim 1 wherein a separate wheel kit isadapted to replace the steerable front skis of the snowmobile andcomprises a rigid front axle with a kingpin at each end supportingcorresponding steerable wheels spaced outwardly of the position for thesnowmobile chassis, means adapted to connect said steerable wheels withthe steering mechanism for the snowmobile skis, and means adapted toresiliently support the front end of said snowmobile chassis upon saidfront axle.
 7. A front wheel kit adapted for replacement of the frontskis of a snowmobile, comprising a rigid transversely extending frameadapted to be secured to the underside of the snowmobile when the frontskis and their mountings have been removed, a front wheel axle havingkingpins for separately mounting front steerable wheels at its oppositeends, means adapted to connect the steering knuckles of said wheels tothe steering control mechanism of the snowmobile, and rEsilient meansmounting said axle to said frame and providing for limited relativevertical movement between said axle and said frame.
 8. The front wheelkit of claim 7 in which said last named means comprises a pair of leafsprings secured at their forward ends to the opposite ends of said axleand secured at their rear ends to said rigid frame near the longitudinalcenter line thereof.
 9. A wheel mounting for snowmobiles having forwardskis and a track drive with a forward sprocket drive shaft, comprisingin combination a front wheel kit adapted to replace the forward skis ofthe snowmobile and a rear wheel kit adapted to replace the track drivefor the snowmobile, means mounting said rear wheel kit for verticalpivotal swinging on the sprocket drive shaft near the forward end of thesnowmobile with the wheels disposed beyond the rear end of thesnowmobile and driven from said shaft, and means rigidly mounting saidfront wheel kit to the bearing supports for said sprocket drive shaft,whereby torsional forces between the front and rear wheels are resistedto provide greater stability for the snowmobile when the wheel kits aresecured thereto.